The category was introduced in 1981 [2] and was initially known as Group N (Appendix J) Saloon Cars (Pre 1965).[3] Cars had to be series production type saloons with seating for four, manufactured prior to 31 December 1964, of which at least 100 had been produced.[3] Mechanical modifications were permitted with the intention of emulating racing under the Appendix J regulations which were current in Australia until 31 December 1964.[3]

The eligibility criteria were amended in 1995 to include cars built up to 31 December 1972.[4]